xen/gntdev: Make private routines/structures accessible

This is in preparation for adding support of DMA buffer
functionality: make map/unmap related code and structures, used
privately by gntdev, ready for dma-buf extension, which will re-use
these. Rename corresponding structures as those become non-private
to gntdev now.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

2 files changed, 131 insertions, 91 deletions

diff --git a/drivers/xen/gntdev-common.h b/drivers/xen/gntdev-common.h
new file mode 100644
index 000000000000..2346c198f72e
--- /dev/null
+++ b/drivers/xen/gntdev-common.h
@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Common functionality of grant device.
+ *
+ * Copyright (c) 2006-2007, D G Murray.
+ *           (c) 2009 Gerd Hoffmann <kraxel@redhat.com>
+ *           (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.
+ */
+
+#ifndef _GNTDEV_COMMON_H
+#define _GNTDEV_COMMON_H
+
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/mmu_notifier.h>
+#include <linux/types.h>
+
+struct gntdev_priv {
+        /* Maps with visible offsets in the file descriptor. */
+        struct list_head maps;
+        /*
+         * Maps that are not visible; will be freed on munmap.
+         * Only populated if populate_freeable_maps == 1
+         */
+        struct list_head freeable_maps;
+        /* lock protects maps and freeable_maps. */
+        struct mutex lock;
+        struct mm_struct *mm;
+        struct mmu_notifier mn;
+
+#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
+        /* Device for which DMA memory is allocated. */
+        struct device *dma_dev;
+#endif
+};
+
+struct gntdev_unmap_notify {
+        int flags;
+        /* Address relative to the start of the gntdev_grant_map. */
+        int addr;
+        int event;
+};
+
+struct gntdev_grant_map {
+        struct list_head next;
+        struct vm_area_struct *vma;
+        int index;
+        int count;
+        int flags;
+        refcount_t users;
+        struct gntdev_unmap_notify notify;
+        struct ioctl_gntdev_grant_ref *grants;
+        struct gnttab_map_grant_ref   *map_ops;
+        struct gnttab_unmap_grant_ref *unmap_ops;
+        struct gnttab_map_grant_ref   *kmap_ops;
+        struct gnttab_unmap_grant_ref *kunmap_ops;
+        struct page **pages;
+        unsigned long pages_vm_start;
+
+#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
+        /*
+         * If dmabuf_vaddr is not NULL then this mapping is backed by DMA
+         * capable memory.
+         */
+
+        struct device *dma_dev;
+        /* Flags used to create this DMA buffer: GNTDEV_DMA_FLAG_XXX. */
+        int dma_flags;
+        void *dma_vaddr;
+        dma_addr_t dma_bus_addr;
+        /* Needed to avoid allocation in gnttab_dma_free_pages(). */
+        xen_pfn_t *frames;
+#endif
+};
+
+struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count,
+                                          int dma_flags);
+
+void gntdev_add_map(struct gntdev_priv *priv, struct gntdev_grant_map *add);
+
+void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map);
+
+bool gntdev_account_mapped_pages(int count);
+
+int gntdev_map_grant_pages(struct gntdev_grant_map *map);
+
+#endif
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 173332f439d8..e03f50052f3e 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -6,6 +6,7 @@
  *
  * Copyright (c) 2006-2007, D G Murray.
  *           (c) 2009 Gerd Hoffmann <kraxel@redhat.com>
+ *           (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -26,10 +27,6 @@
 #include <linux/init.h>
 #include <linux/miscdevice.h>
 #include <linux/fs.h>
-#include <linux/mm.h>
-#include <linux/mman.h>
-#include <linux/mmu_notifier.h>
-#include <linux/types.h>
 #include <linux/uaccess.h>
 #include <linux/sched.h>
 #include <linux/sched/mm.h>
@@ -50,6 +47,8 @@
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
 
+#include "gntdev-common.h"
+
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
               "Gerd Hoffmann <kraxel@redhat.com>");
@@ -65,73 +64,23 @@ static atomic_t pages_mapped = ATOMIC_INIT(0);
 static int use_ptemod;
 #define populate_freeable_maps use_ptemod
 
-struct gntdev_priv {
-        /* maps with visible offsets in the file descriptor */
-        struct list_head maps;
-        /* maps that are not visible; will be freed on munmap.
-         * Only populated if populate_freeable_maps == 1 */
-        struct list_head freeable_maps;
-        /* lock protects maps and freeable_maps */
-        struct mutex lock;
-        struct mm_struct *mm;
-        struct mmu_notifier mn;
-
-#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
-        /* Device for which DMA memory is allocated. */
-        struct device *dma_dev;
-#endif
-};
-
-struct unmap_notify {
-        int flags;
-        /* Address relative to the start of the grant_map */
-        int addr;
-        int event;
-};
-
-struct grant_map {
-        struct list_head next;
-        struct vm_area_struct *vma;
-        int index;
-        int count;
-        int flags;
-        refcount_t users;
-        struct unmap_notify notify;
-        struct ioctl_gntdev_grant_ref *grants;
-        struct gnttab_map_grant_ref   *map_ops;
-        struct gnttab_unmap_grant_ref *unmap_ops;
-        struct gnttab_map_grant_ref   *kmap_ops;
-        struct gnttab_unmap_grant_ref *kunmap_ops;
-        struct page **pages;
-        unsigned long pages_vm_start;
-
-#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
-        /*
-         * If dmabuf_vaddr is not NULL then this mapping is backed by DMA
-         * capable memory.
-         */
-
-        struct device *dma_dev;
-        /* Flags used to create this DMA buffer: GNTDEV_DMA_FLAG_XXX. */
-        int dma_flags;
-        void *dma_vaddr;
-        dma_addr_t dma_bus_addr;
-        /* Needed to avoid allocation in gnttab_dma_free_pages(). */
-        xen_pfn_t *frames;
-#endif
-};
-
-static int unmap_grant_pages(struct grant_map *map, int offset, int pages);
+static int unmap_grant_pages(struct gntdev_grant_map *map,
+                             int offset, int pages);
 
 static struct miscdevice gntdev_miscdev;
 
 /* ------------------------------------------------------------------ */
 
+bool gntdev_account_mapped_pages(int count)
+{
+        return atomic_add_return(count, &pages_mapped) > limit;
+}
+
 static void gntdev_print_maps(struct gntdev_priv *priv,
                               char *text, int text_index)
 {
 #ifdef DEBUG
-        struct grant_map *map;
+        struct gntdev_grant_map *map;
 
         pr_debug("%s: maps list (priv %p)\n", __func__, priv);
         list_for_each_entry(map, &priv->maps, next)
@@ -141,7 +90,7 @@ static void gntdev_print_maps(struct gntdev_priv *priv,
 #endif
 }
 
-static void gntdev_free_map(struct grant_map *map)
+static void gntdev_free_map(struct gntdev_grant_map *map)
 {
         if (map == NULL)
                 return;
@@ -176,13 +125,13 @@ static void gntdev_free_map(struct grant_map *map)
         kfree(map);
 }
 
-static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count,
+struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count,
                                           int dma_flags)
 {
-        struct grant_map *add;
+        struct gntdev_grant_map *add;
         int i;
 
-        add = kzalloc(sizeof(struct grant_map), GFP_KERNEL);
+        add = kzalloc(sizeof(*add), GFP_KERNEL);
         if (NULL == add)
                 return NULL;
 
@@ -252,9 +201,9 @@ err:
         return NULL;
 }
 
-static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add)
+void gntdev_add_map(struct gntdev_priv *priv, struct gntdev_grant_map *add)
 {
-        struct grant_map *map;
+        struct gntdev_grant_map *map;
 
         list_for_each_entry(map, &priv->maps, next) {
                 if (add->index + add->count < map->index) {
@@ -269,10 +218,10 @@ done:
         gntdev_print_maps(priv, "[new]", add->index);
 }
 
-static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
-                int index, int count)
+static struct gntdev_grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
+                                                      int index, int count)
 {
-        struct grant_map *map;
+        struct gntdev_grant_map *map;
 
         list_for_each_entry(map, &priv->maps, next) {
                 if (map->index != index)
@@ -284,7 +233,7 @@ static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
         return NULL;
 }
 
-static void gntdev_put_map(struct gntdev_priv *priv, struct grant_map *map)
+void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map)
 {
         if (!map)
                 return;
@@ -315,7 +264,7 @@ static void gntdev_put_map(struct gntdev_priv *priv, struct grant_map *map)
 static int find_grant_ptes(pte_t *pte, pgtable_t token,
                 unsigned long addr, void *data)
 {
-        struct grant_map *map = data;
+        struct gntdev_grant_map *map = data;
         unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
         int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte;
         u64 pte_maddr;
@@ -348,7 +297,7 @@ static int set_grant_ptes_as_special(pte_t *pte, pgtable_t token,
 }
 #endif
 
-static int map_grant_pages(struct grant_map *map)
+int gntdev_map_grant_pages(struct gntdev_grant_map *map)
 {
         int i, err = 0;
 
@@ -413,7 +362,8 @@ static int map_grant_pages(struct grant_map *map)
         return err;
 }
 
-static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
+static int __unmap_grant_pages(struct gntdev_grant_map *map, int offset,
+                               int pages)
 {
         int i, err = 0;
         struct gntab_unmap_queue_data unmap_data;
@@ -448,7 +398,8 @@ static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
         return err;
 }
 
-static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
+static int unmap_grant_pages(struct gntdev_grant_map *map, int offset,
+                             int pages)
 {
         int range, err = 0;
 
@@ -480,7 +431,7 @@ static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
 
 static void gntdev_vma_open(struct vm_area_struct *vma)
 {
-        struct grant_map *map = vma->vm_private_data;
+        struct gntdev_grant_map *map = vma->vm_private_data;
 
         pr_debug("gntdev_vma_open %p\n", vma);
         refcount_inc(&map->users);
@@ -488,7 +439,7 @@ static void gntdev_vma_open(struct vm_area_struct *vma)
 
 static void gntdev_vma_close(struct vm_area_struct *vma)
 {
-        struct grant_map *map = vma->vm_private_data;
+        struct gntdev_grant_map *map = vma->vm_private_data;
         struct file *file = vma->vm_file;
         struct gntdev_priv *priv = file->private_data;
 
@@ -512,7 +463,7 @@ static void gntdev_vma_close(struct vm_area_struct *vma)
 static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma,
                                                  unsigned long addr)
 {
-        struct grant_map *map = vma->vm_private_data;
+        struct gntdev_grant_map *map = vma->vm_private_data;
 
         return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT];
 }
@@ -525,7 +476,7 @@ static const struct vm_operations_struct gntdev_vmops = {
 
 /* ------------------------------------------------------------------ */
 
-static void unmap_if_in_range(struct grant_map *map,
+static void unmap_if_in_range(struct gntdev_grant_map *map,
                               unsigned long start, unsigned long end)
 {
         unsigned long mstart, mend;
@@ -554,7 +505,7 @@ static void mn_invl_range_start(struct mmu_notifier *mn,
                                 unsigned long start, unsigned long end)
 {
         struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
-        struct grant_map *map;
+        struct gntdev_grant_map *map;
 
         mutex_lock(&priv->lock);
         list_for_each_entry(map, &priv->maps, next) {
@@ -570,7 +521,7 @@ static void mn_release(struct mmu_notifier *mn,
                        struct mm_struct *mm)
 {
         struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
-        struct grant_map *map;
+        struct gntdev_grant_map *map;
         int err;
 
         mutex_lock(&priv->lock);
@@ -651,13 +602,14 @@ static int gntdev_open(struct inode *inode, struct file *flip)
 static int gntdev_release(struct inode *inode, struct file *flip)
 {
         struct gntdev_priv *priv = flip->private_data;
-        struct grant_map *map;
+        struct gntdev_grant_map *map;
 
         pr_debug("priv %p\n", priv);
 
         mutex_lock(&priv->lock);
         while (!list_empty(&priv->maps)) {
-                map = list_entry(priv->maps.next, struct grant_map, next);
+                map = list_entry(priv->maps.next,
+                                 struct gntdev_grant_map, next);
                 list_del(&map->next);
                 gntdev_put_map(NULL /* already removed */, map);
         }
@@ -674,7 +626,7 @@ static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
                                        struct ioctl_gntdev_map_grant_ref __user *u)
 {
         struct ioctl_gntdev_map_grant_ref op;
-        struct grant_map *map;
+        struct gntdev_grant_map *map;
         int err;
 
         if (copy_from_user(&op, u, sizeof(op)) != 0)
@@ -688,7 +640,7 @@ static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
         if (!map)
                 return err;
 
-        if (unlikely(atomic_add_return(op.count, &pages_mapped) > limit)) {
+        if (unlikely(gntdev_account_mapped_pages(op.count))) {
                 pr_debug("can't map: over limit\n");
                 gntdev_put_map(NULL, map);
                 return err;
@@ -715,7 +667,7 @@ static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
                                          struct ioctl_gntdev_unmap_grant_ref __user *u)
 {
         struct ioctl_gntdev_unmap_grant_ref op;
-        struct grant_map *map;
+        struct gntdev_grant_map *map;
         int err = -ENOENT;
 
         if (copy_from_user(&op, u, sizeof(op)) != 0)
@@ -741,7 +693,7 @@ static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
 {
         struct ioctl_gntdev_get_offset_for_vaddr op;
         struct vm_area_struct *vma;
-        struct grant_map *map;
+        struct gntdev_grant_map *map;
         int rv = -EINVAL;
 
         if (copy_from_user(&op, u, sizeof(op)) != 0)
@@ -772,7 +724,7 @@ static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
 static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
 {
         struct ioctl_gntdev_unmap_notify op;
-        struct grant_map *map;
+        struct gntdev_grant_map *map;
         int rc;
         int out_flags;
         unsigned int out_event;
@@ -1070,7 +1022,7 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
         struct gntdev_priv *priv = flip->private_data;
         int index = vma->vm_pgoff;
         int count = vma_pages(vma);
-        struct grant_map *map;
+        struct gntdev_grant_map *map;
         int i, err = -EINVAL;
 
         if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
@@ -1127,7 +1079,7 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
                 }
         }
 
-        err = map_grant_pages(map);
+        err = gntdev_map_grant_pages(map);
         if (err)
                 goto out_put_map;